Some of the gitignore file patters were explicitly meant to be only for
the top level, but weren't marked that way, so they would trigger
recursively in subdirectories too.  Normally that was harmless, but at
least "linux" happened to trigger elsewhere too. Fix it up.

And other patterns in that section weren't necessarily top-level at all.
Reported-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>